Disazo pigments and method of producing



Patented Nov. 30, 1943 DISAZO PIGMENTS AND METHOD OF PRODUCING WilliamB. Reynolds, Cincinnati, Ohio, assignor to Interchemical Corporation,New York, N. Y., a corporation of Ohio No Drawing. Application November14, 1942, Serial No. 465,631

2 Claims.

This invention relates to disazo pigments, and has particular referenceto new pigments characterized by cleanliness of tone combined withfastness to light and resistance to bleeding in organic solvents.Specifically, this invention relates to the coppery complexes obtainablefrom the couplings of beta oxy naphthoic acid with certain tetrazotizedprimary aromatic diamines.

There has been considerable demand, particularly in the field of pigmentprinting on textiles, for pigments which would combine the features ofbrilliance of tone, 'fastness to light, and resistance to solvents suchas acetone, while showing extremely good resistance to Water and dilutesoap solutions. In particular, acceptable browns and violets have beendifiicult to obtain unless insoluble vat dyestuffs are used.

In my co-pending application Serial Number 340,046, filed June 12, 1940,of which this is a continuation in part, I have disclosed the inventionof certain azo pigments which combine cleanliness of color withlightfastness, wash-resistance and insolubility in organic solvents.These pigments comprise the coppered complexes of the couplings of betaoxy naphthoic acid with tetrazotized primary aromatic diamines of thegeneral formula:

Where R and R are benzene or naphthalene nuclei, X and X aresubstituents of the group consisting of hydrogen, alkyl, alkoxy, halogenand nitro, n and n are numbers from 1 to 3, and Y is a bond, oxygen,carbonyl or alkyl. In that application, it was also disclosed that X1and X2 could be aryl and aralkyl, although no specific examples of thisclass of substituents were therein disclosed.

This disclosure is directed to azo pigments of the above class, of thegeneral formula:

COOH HOOO where R and R are benzene or naphthalene nuclei, n and n arenumbers from 1 to 3, and Y is a bond, oxygen, carbonyl or alkyl.

Typical amines which can be used are 3,3- diphenyl benzidine,3,3'-diphenyl-4,4'-diamino diphenyl ether; 3,3'-diphenyl-4,4:-diaminobenzophenone; 3,3-diphenyl-4,4-diamino diphenyl methane; 3,3 diphenyl4,4'-diamino 1,1-binaphthyl, and certain derivatives of the above typescontaining substituents of the type alkyl, alkoxy, halogen, and nitroproviding such substituents do not inhibit azotization of the aminogroups.

Typical examples of my invention are the following:

4.09 gins. (9.09 gins. 45% paste) (.01 M) diphenyl benzidinehydrochloride (Carwin Company) were tetrazotized in the usual mannerusing hydrochloric acid, Water and sodium nitrite as the azotizingmedium.

The azotized diamine was then coupled to a solution made up of 3.76 gms.(.02 M) beta hydroxy naphthoic acid, .8 gm. NaOH, 7.62 gms. soda ash,water and ice.

The resulting pigment, after stirring to allow completeness of coupling,was heated to C., and then struck with a water solution of .06 MCuSO4-5H2O; the whole was heated at near boil for one hour, filtered andwashed.

The material was a pigment of a deep reddish purple color.

The typical precautionary measures useful in diazotization reactionsshould be observed, these varying of course with the particular amine.In coupling, I prefer to operate with the beta oxy naphthoic acidpartially out of solution, as I find that improved results are obtainedin more concentrated coupling solutions.

The copper probably couples by forming a complex between the phenolichydroxyl and the carboxyl group. I find that about 10 to 15% excess ofcopper is desirable over that necessary to produce the theoreticalequi-molar complex with the beta-cxy naphthoic acid (i. e. two mols ofcopper per mol of dyestuil). The coppering can take place in neutral oralkaline solutions (pH 7.0 or higher), the copper may be present as asimple salt, or as a complex such as the copper ammonium complex. Ingeneral, rather elevated temperates (GO- C.) are necessary to insurecomplete coppering.

Obviously, many changes can be made in the specific example withoutdeparting from the scope of the invention, which is defined in theclaims.

I claim:

1. The method of making a pigment dyestufi, which comprisestetrazotizing a diamine of the formula:

where n and n are numbers from 1 to 3, Y is a connecting member of thegroup consisting of a bond, oxygen, carbonyl and alkyl, and R and R arenuclei of the group consisting of benzene and naphthalene, coupling thetetrazo compound with beta hydroxy naphthoic acid, and coppering insubstance the azo compound so produced.

general formula:

COOH

HOOC

where n and n are numbers from i to 3, Y is a connecting member of thegroup consisting of a bond, oxygen, carbonyl and alkyl, and. R and R arenuclei of the group consisting of benzene and naphthalene, in the formof finely divided waterinsoluble pigment powders.

WILLIAM B. REYNOLDS.

